Control device and control method for a vehicle

ABSTRACT

At the time of the change-speed, by correcting the torque reducing portion of an output shaft during the change-speed, the revolution number of an input shaft is controlled on the basis of the corrected torque reduction correcting value. Also, the torque of said input shaft is adjusted at the end of the change-speed on the basis of said torque correcting value.

BACKGROUND OF THE INVENTION

This application is a continuation of application Ser. No. 10/730,028filed Dec. 9, 2003, which is a continuation of application Ser. No.10/377,751, filed Mar. 4, 2003, which is a continuation of applicationSer No. 10/058,383, filed Jan. 30, 2003, (now U.S. Pat. No. 6,449,546)which is a continuation of application Ser. No. 09/652,658, filed Aug.31, 2000, (now U.S. Pat. No. 6,560,521)

This invention relates to a control device for a vehicle 5 and controlmethod for a vehicle.

Japanese Patent Application Laid-Open No.61-45163 (1986) describes acontrol device for a vehicle using a gear type transmission. Thiscontrol device is constructed to achieve smooth speed changing byincluding a friction clutch on a gear providing the minimum change-speedratio to the gear type transmission, controlling the number ofrevolution of the input shaft of the transmission by sliding saidfriction clutch during the change-speed to synchronize it with thenumber of revolution of the output shaft of the transmission, andcorrecting torque reduction occurring during the change-speed with thetorque transmitted by said friction clutch.

However, in the prior art control device there is a problem that ifduring the change-speed the control of the number of revolution only byusing the friction clutch, a occupant would receive a sense ofincompatibility due to fluctuation of the torque of the output shaftcorrected by the friction clutch.

Also, there is a problem that, of the end of the speed, if the torquereduction correcting value during the change-speed corrected by thefriction clutch does not match to the torque of the input shaft which istransmitted to the output shaft by a claw clutch, a torque step iscaused at the time of the change-speed whereby shaft vibration isgenerated after the change-speed.

SUMMARY OF THE INVENTION

An object of this invention is to improve transmission ability for avehicle by suppressing the fluctuation of the torque of the output shaftcaused from the control of the number of revolution during thechange-speed and by reducing a torque step at the end of thechange-speed.

This invention relates to a control device for a vehicle having torquetransmitting means between the input shaft of a gear type transmissionand the output shaft thereof. The torque transmitting means of at leastone speed changing stage is comprised by a friction clutch, while thetorque transmitting means of the other speed changing stages arecomprised by a mesh type clutch. The friction clutch is controlled whenthe change-speed is effected from the one speed changing stage to theother changing stage. The control device according to the inventioncomprises torque reduction correcting means, operative, at the time ofsaid change-speed, for correcting the torque reducing part of saidoutput shaft occurring during the change-speed, and revolution numbercontrolling means for controlling the revolution number of said inputshaft on the basis of the torque reduction correcting value corrected bysaid torque reduction correcting means.

Further, the control device according to this invention is characterizedin that it further comprises torque adjusting means for adjusting thetorque of said input shaft at the end of the change-speed on the basisof said torque reduction correcting value.

Also, this invention relates to a control method for a vehicle whereintorque transmitting means is attached between the input shaft of a geartype transmission and the output shaft thereof. The torque transmittingmeans of at least one speed changing stage is comprised by a frictionclutch, while the torque transmitting means of the other speed changingstages are comprised by a mesh type clutch. The friction clutch iscontrolled when the change-speed is effected from the one speed changingstage to the other changing stage.

The control method according to the invention comprises the steps ofcorrecting, at the time of said change-speed, the torque reducing partof said output shaft occurring during the change-speed, and controllingthe revolution number of said input shaft on the basis of the torquereduction correcting value corrected by said torque reduction correctingmean.

Further, the control method according to this invention is characterizedin that it further comprises the step of adjusting the torque of saidinput shaft at the end of the change-speed on the basis of said torquereduction correcting value.

Other objects, advantages and novel features of the present inventionwill become apparent from the following detailed description of theinvention when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a vehicle system and its control devicewhich is one embodiment of this invention;

FIG. 2 is a diagram showing a torque transmitting path in case where thevehicle is running by the driving power of an engine;

FIG. 3 is a diagram showing a torque transmitting path duringchange-speed;

FIG. 4 is a diagram showing a torque transmitting path after the end ofthe change-speed;

FIG. 5 is a flow chart of control processes in the torque reductioncorrecting means of the control device according to one embodiment ofthis invention;

FIG. 6 is a flow chart of control processes in the revolution numbercontrolling means and the torque adjusting means of the control deviceaccording to one embodiment of this invention;

FIG. 7 is a time chart showing the control state at the time of thechange-speed in one embodiment of this invention;

FIG. 8 is a block diagram of a control device for a vehicle according tothe other embodiment of this invention;

FIG. 9 is a diagram showing a torque transmitting path during thechange-speed in the other embodiment of this invention;

FIG. 10 is a flow chart showing control processes in the revolutionnumber means and the torque adjusting means of the control device forthe vehicle according to the other embodiment of this invention; and

FIG. 11 is a time chart showing a control state during the change-speedin the other embodiment of this invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of this invention will be explained in detail on the basisof the drawings.

FIG. 1 is a block diagram for a vehicle system and its control deviceaccording to one embodiment of this invention.

An engine 1 includes an electronically controlling throttle 2 foradjusting engine torque and a revolution or engine speed sensor 37 formeasuring the number of revolution of the engine 1, Ne. Thus, it ispossible to control the output torque of the engine with a high degreeof accuracy.

A clutch 4 is attached between the output shaft 3 of the engine 1 andthe input shaft 8 of a gear type transmission 50 so that the torque ofthe engine 1 can be transmitted to the input shaft 8. The clutch 4 asused is of a dry single plate type, in order to control the pressingpressure of the clutch 4 a hydraulically driven actuator 32 is utilized,and power transmission from the output shaft 3 of the engine 1 to theinput shaft 8 can be interrupted by adjusting the pressure of the clutch4.

The input shaft 8 has gears 5, 6 and 7 attached thereto.

The gear 5 is used also as a detector for detecting the number ofrevolution of the input shaft 8, Nin. It is possible to detect therevolution of the input shaft 8, by detecting the movement of the teethof the gear 5 with a sensor 36.

A motor 27 has an output shaft 26 to which a gear 24 having a clutch 25is connected. The gear 24 is adapted to engage with the gear 7 all thetime. The clutch 25 as used is of a dry single plate type which enablesthe transmission of the output torque of the motor 27 to the gear 24.The control of the pressure of the clutch 25 is performed by an actuator29 which is hydraulically driven, and power transmission from the outputshaft 26 to the input shaft 8 can be interrupted by adjusting thepressure of the clutch 25.

The gear type transmission 50 includes an output shaft 20 whichcomprises a gear 18 having a gear 14 and a synchronizer ring 16, a gear11 having a gear 12 and a synchronizer ring 15, a hub 17 directlycoupling the gear 18 and a gear 11 to the output shaft 20, and a sleeve(not shown). The gear 18 and the gear 11 have respective stoppers (notshown) for preventing any movement thereof in the axial direction on theoutput shaft 20. Further, this hub 17 has inside grooves (not shown)engaging with a plurality of grooves (not shown) of the output shaft 20,whereby the hub 17 is coupled to the output shaft 20 so that the formercan relatively move axially with respect to the latter but any relativemovement in the rotational direction is limited. Therefore, the torqueof the hub 17 is transmitted to the output shaft 20.

In order to transmit the torque from the input shaft to the hub 17, itis needed to move the hub 17 and the sleeve in the axial direction withrespect to the output shaft 20 to couple directly the hub 17 to the gear14 or the gear 12 through the synchronizer ring 16 or the synchronizerring 15. A hydraulically driven actuator 30 is used to move the hub 17and the sleeve.

The hub 17 is also used as a detector for detecting the number ofrevolution No of the output shaft 20. In this case, it is possible todetect the revolution number of the output shaft 20 by detecting therevolution of the hub 17 with a sensor 13.

A claw clutch mechanism acting as torque transmitting means comprisingthe hub 17 and the sleeve; the gear 14 and the synchronizer ring 16; andthe gear 12 and synchronizer ring 15 is referred to a mesh type clutch.

This mechanism enables to transmit energy from a power source such asthe engine 1 to a tire 23 through a differential device 21 and an axle22 with high efficiency, thereby to aid in 5 decreasing fuelconsumption.

Further, the output shaft 20 includes a gear 9 having clutch 10. Theclutch 10 is constituted by a wet type multiple plate type frictionclutch so that the torque of the input shaft 8 can be transmitted to theoutput shaft 20. The control of the pressure of the clutch 10 isperformed by an actuator 32 which is hydraulically driven, and powertransmission from the input shaft 8 to the output shaft 20 can beinterrupted by adjusting this pressure.

The speed changing ratio of the gear 5 and the gear 9 is made smallerthan the speed changing ratio of the gear 7 and the gear 18, and thespeed changing ratio of the gear 6 and the gear 11.

In the engine 1, the amount of intake air is controlled by theelectronically controlled throttle 2 attached to an intake pipe (notshown), and the fuel of the amount corresponding to the amount of intakeair is injected from a fuel injecting device (not shown). Also, ignitiontiming is determined on the basis of an air fuel ration defined by theamount of air and the amount of fuel as well as signals such as thenumber of revolution of the engine, Ne, and ignition is effected by anignition device (not shown).

As the fuel injection device, there are an intake port fuel injectingsystem in which fuel is injected to an intake port, and a cylinder fuelinjecting system in which fuel is injected directly into a cylinder, butit is preferable to select a system which enables to decrease fuelconsumption and is superior to exhaust gas ability, comparing operationareas (areas determined by the engine torque and the engine revolutionnumber) required by the engine.

Next, a control device 100 will be explained for controlling the engine1, the actuators 29, 30, 31 and 32, and the motor 27.

The control device 100 receives as input signals an accelerator pedalcontrolling amount signal, a shift lever position signal Ii, an enginerevolution number signal Ne detected by a sensor 37, an input shaftrevolution number signal Nin detected by a sensor 36 and an output shaftrevolution number signal No detected by a sensor 13. In responsethereto, the control device 100 computes the torque Te of the engine 1,and sends it to a control device 34 through a LAN constitutingcommunication means.

The control device 34 computes the degree of throttle valve opening, theamount of fuel and ignition timing for achieving the received enginetorque, and controls respective actuators (for example, theelectronically controlled throttle 2).

Also, the control device 100 computes the torque and the number ofrevolution of the motor 27, and sends them to a control device 35through the LAN to control the motor. The control device 35 functions tocharge a battery 28 with power obtained from the motor 27 and supply apower from the battery 28 to the motor 27 for driving it.

The control device 100 comprises vehicle speed detecting means 101,change-speed command generating means, torque reduction correcting means103, revolution number controlling means 104 and torque adjusting means105.

The vehicle speed detecting means 101 computes the vehicle speed Vsp onthe basis of the output shaft revolution number No detected by thesensor 13 (in this case, the computation is performed as Vsp=f(Nm) usingfunction f).

The change-speed command generating means 102 determines a speedchanging command Ss on the basis of the input accelerator pedalcontrolling amount and the vehicle speed Vsp found by the vehicle speeddetecting means 101. The speed changing command Ss is selected fromvalues stored in memory means (not shown) within the control device 100,said values being found by a pre-experiment or a simulation as onesgiving the maximum efficiency to the engine 1 and motor 27.

Now, the control of the clutch 10 will be explained when the speedchanging stages is altered (speed changed) from first (1) speedoperation state to second speed (2) operation state, using FIG. 2, FIG.3 and FIG. 4. The control of the clutch 10 is effected by controllingthe actuators 29 to 32 on the basis of the commands from the controldevice 100 so that the control device 33 controls the gear typetransmission 50.

FIG. 2 is a view for explaining the first state operation speed in casewhere the vehicle is intended to be accelerated when it runs with thedriving force of the engine 1. In the drawings, dotted arrow linesindicate torque transmitting paths. As one example, it is assumed wherethe clutch 4 has been coupled and the mesh type clutch (hub 17) has beencoupled to the gear 18. In this condition, the torque of the engine 1 istransmitted to the output shaft 20 trough the clutch 4, the input shaft8, the gear 7 and the gear 18. At that time, the clutch 10 is in thereleased condition.

When the change-speed command Ss is output by the change-speed commandgenerating means 102, the mesh type clutch (hub 17) is made the releasedcondition to release the coupling between the gear 18 and the outputshaft 20, as shown in FIG. 3. At the same time, the actuator 31 iscontrolled to press and couple the clutch 10, thereby to transmit thetorque of the engine 1 from the output shaft 3 through the clutch 4, theinput shaft 8, the gear 5, the gear 9 and the clutch 10 to the outputshaft 20. Thus, when the torque of the engine 1 is transmitted to theaxle 22 with the pressing pressure of the clutch 10 to make it thedriving torque for the vehicle, the gears 5 and 9 are used and the speedchanging ratio becomes smaller. As a result, the load of the engine 1becomes larger and the number of revolution decreases, whereby the speedchanging ratio between the output shaft 20 and the input shaft 8 leavesthe speed changing ratio of the first speed and approaches to the speedchanging ratio of the second speed (the direction that the speedchanging ratio becomes smaller).

Then, when the speed changing ratio between the input shaft 8 and theoutput shaft 20 becomes the change-speed ratio of the second speed, themesh type clutch (hub 17) is coupled to the gear to couple the gear 11to the output shaft 20, as shown in FIG. 4. As soon as this coupling iscompleted, the actuator 31 is controlled so that the change-speed fromthe first speed to the second speed is completed by releasing thepressure of the clutch 10. In this second speed operation state, thetorque of the engine 1 is transmitted through the transmitting pathpassing the output shaft 3 of the engine 1, the clutch 4, the inputshaft 8, the gear 6, the gear 11, the hub 17 and the output shaft 20 inthe order.

From the above-mentioned explanation, it is appreciated that although atthe time of the change-speed a neutral state is created by releasing thefirst speed condition, since at that time the torque of the engine I isadapted to be transmitted to the axle 22 by the clutch 10 and the gears5 and 9, it is possible to correct any torque reduction occurring duringthis change-speed.

Now, a control method at the time of the change-speed in the vehiclecontrol device of this embodiment will be explained by using FIG. 5 toFIG. 7.

First, control processes in the torque reduction correcting means 103will be explained.

FIG. 5 is a flow chart for the control processes in the torque reductioncorrecting means 103.

Step 501

In this step, a change-speed command Ss output from the change-speedcommand generating means 102 is read.

Step 502

In this step, the torque Tel of the engine 1 before the change-speed(during the first speed), received by the control device 34 through theLAN is read.

Step 503

In this step, the torque Toutl of the output shaft 20 before thechange-speed (during the first speed) is computed on the basis of thetorque Tel of the engine 1 before the change-speed, read in Step 502.

Step 504

In this step, the FF (Feed Forward) target torque Tc_ff of the clutch 10is computed on the basis of the torque Toutl of the output shaft 20computed in Step 503. Also, assuming that the change-speed ratio at thefirst speed is referred to R1, the change-speed ratio at the secondspeed is referred to R2, the engine revolution number before thechange-speed is referred to Ne1 and the engine revolution number afterthe change-speed (at the time of the second speed) is referred to Ne2,the engine revolution number Ne2 after the change-speed may be presumedas Ne2 Ne1×(R2/R1). Further, it is possible to find the engine torqueafter the change-speed in response to the presumed engine revolutionnumber Ne2 and the amount of throttle opening, and the output shafttorque after the change-speed, Tout 2 can be also presumed. It ispossible to compute the FF target torque Tc_ff of the clutch 10depending upon this presumed torque Tout2.

Step 505

In this step, it is determined whether an input/output shaft revolutionnumber ratio Rch which is found by the engine revolution number Ne(input shaft revolution number Nin) and the output shaft revolutionnumber No is within a predetermined range. If it is not within thepredetermined range, the process proceeds to Step 506, and if it iswithin the predetermined range, the process proceeds to Step 508.

Step 506

In this step, in case where during the change-speed the input/outputshaft revolution number ratio Rch is not within the predetermined range,the torque reduction correcting value during the change-speed, Tc_ref iscomputed as Tc-ref=Tc_ff.

Step 507

In this step, in case where during the change-speed the input/outputshaft revolution number ratio Rch is within the predetermined range, byfeeding back an error between the target revolution number ratiocorresponding to the change-speed ratio of the second speed and theinput/output shaft revolution number ratio Rch, the revolution numberratio FB (Feed Back) target torque Tc_fb is computed. At that time, therevolution number ratio FB target Tc_fb of the clutch 10 may be computedby computing the target engine revolution number (input shaft revolutionnumber) depending upon the target revolution number ratio and feedingback the engine revolution number Ne.

Step 508

In this step, the torque reduction correcting value Tc_ref during thechange-speed is computed as Tc-ref=Tc-ff+Tc-f b.

Step 509

In this step, the torque reduction correcting value Tc_ref during thechange-speed Tc-ref found in Step 506 and Step 508 is output as thetarget torque of the clutch 10. The output torque reduction correctingvalue Tc-ref is sent to the control device 33 through the LAN.

The control device 33 is a control device for driving hydraulically theactuators 29 to 33, and controls the actuator 31, thereby to correct anytorque reducing part during the change-speed on the basis of the valueof Tc_ref by adjusting the pressing pressure of the clutch 10.

As explained above, in the torque reduction correcting means, it ispossible to improve change-speed ability by correcting the torquereducing portion of the output shaft 20 occurring during thechange-speed.

Next, control processes in the revolution number controlling means 104and the torque adjusting means 105 will be explained.

FIG. 6 is a flow chart for the control processes in the revolutionnumber controlling means 104 and the torque adjusting means 105.

Step 601

In this step, it is determined whether the input/output shaft revolutionnumber ratio Rch found on the basis of the engine revolution number Ne(input shaft revolution number Nin) and the output shaft revolutionnumber No is within a predetermined range. If it is not within thepredetermined range, the process proceeds to Step 602 in which controlprocesses are preformed by the revolution number controlling means 104,and if it is within the predetermined range, the process proceeds toStep 603 in which control processes are performed by the torqueadjusting means 105.

First, control processes in the revolution number controlling means 104which are effected in Step 602 to Step 604 will be explained.

Step 602

In this step, the torque reduction correcting value Tc-ref foundaccording to Tc_ref=Tc-ff is read.

Step 603

In this step, the target torque of the engine 1, Te-ref1 achieving therevolution number Ne of the engine 1, Ne giving the predeterminedinput/output shaft revolution number ratio Rch is computed on the basisof the torque reduction correcting value Tc-ref as read in Step 602.

Step 604

In this step, the target torque Te-ref1 of the engine 1 found in Step603 is output. The output target torque Te-ref1 of the engine 1 is sentto the control device 34 through the LAN.

The control device 34 controls the electronically controlled throttle 2so that the target torque Te-ref1 of the engine 1 is achieved.

Also, in the revolution number controlling means 104, in order toachieve the target torque Te_ref1I of the engine 1, the air fuel ratioof the engine 1 may be controlled, or ignition timing may be controlled.

As explained above, in the embodiment, it is possible to couple the meshtype clutch as the second condition by controlling the revolution numberof the input shaft 8 during the change-speed using the revolution numbercontrolling means 104, and also to improve change-speed ability bycontrolling inertia torque at the time of the coupling to the secondspeed.

Next, control processes in the torque controlling means 105 effected inStep 605 to Step 607 will be explained.

Step 605

In this step, the torque reduction correcting value Tc-ref foundaccording to Tc_ref=Tc-ff+Tc-fb is read.

Step 606

In this step, the target torque Te_ref2 of the engine 1, making smallera deviation between the output shaft torque after the change-speed andthe torque reduction correcting value Tc-ref is computed on the basis ofthe torque reduction correcting value Tc-ref read in Step 605.

Step 607

In this step, the target torque Te-ref2 of the engine 1 found in Step606 is output. The output target torque Te-ref2 of the engine 1 is sentto the control device 34 through the LAN.

The control device 34 controls the electronically controlled throttle 2so that the target torque Te_ref2 of the engine 1 is achieved.

Also, in the torque adjusting means 105, in order to achieve the targettorque Te_ref2 of the engine 1, the air fuel ratio of the engine 1 maybe controlled, or ignition timing may be controlled.

As explained above, in the torque adjusting means 105, it is possible tomake smaller the deviation between the torque reduction correcting valueduring the change-speed and the torque of the output shaft 20 after thechange-speed by controlling the torque of the input shaft 8 at the endof the change-speed, and also it is possible to improve speed changingability by decreasing the torque step thereby to restrain any shaftvibration or fluctuation after the change-speed.

Next, the operation at the time of the change-speed will be explained.

FIG. 7 is a time chart showing the control condition at the time of thechange-speed. In FIG. 7, (A) shows a speed changing command Ss, (B) ashift lever position corresponding to a mesh type clutch position, (C)the input/output shaft revolution number ratio Rch, (D) the degree ofthrottle opening ⊖, (E) the torque Tc of the clutch 10, and (F) thetorque Tout of the output shaft 20. Also, the axis of abscissarepresents time.

As shown in (A), when during the driving at the first speed thechange-speed command Ss instructing the second speed is output at pointa, the speed changing control is started, and as shown in (E) the torqueTC of the clutch 10 gradually increases.

As the torque Tc of the clutch 10 gradually increases, as shown in (F)the torque Tout of the output shaft 20 gradually decreases and at pointb, the mesh type clutch which has been coupled at the first speed sidebecomes releasable. That is, due to the torque to be transmitted withthe gears 5 and 9, the torque to be transmitted with the gear 7 and 18decreases to a value making the mesh type clutch releasable.

When the mesh type clutch becomes the releasable the mesh type clutchwhich has been coupled at first speed side is released by the control ofthe actuator 30, and the shift lever position Ii becomes a neutral state(during the change-speed), whereby the actual change-speed is initiated.

When the shift lever position Ii becomes the neutral state, as shown in(E) the control of the clutch 10 for correcting the torque reductionpart occurring during the change-speed is started, and the actuator 31is controlled in accordance with the value of the target torqueTc_ref=Tc-ff of the clutch 10 output from the torque reductioncorrecting means 103, whereby as shown in (F) any torque reduction partof the output shaft 20 during the change-speed is corrected.

At that time, since the torque transmitted by the clutch 10 becomesequal to the torque of the output shaft 20, it is preferable that thetarget torque Tc-ref of the clutch 10 has a smooth property to reducethe sense of discomfort which an occupant would receive. Also, it isneeded to control, during the change-speed, the input/output shaftrevolution number ratio Rch rapidly and smoothly so that it becomes thespeed changing ratio R2 of the second speed.

Therefore, in order to obtain the target torque Te-ref1 of the engine 1output by the revolution number controlling means 104, the enginerevolution number Ne is adjusted by controlling the throttle opening sothat it becomes ⊖=⊖_ref1 as shown in (D), whereby the input/outputrevolution number ratio Rch is caused to be close to the speed changingratio R2 of the second speed.

By such control of the clutch 10 and the electronically controlledthrottle 2, as shown in (C) the input/output shaft revolution numberratio Rch becomes R hR2 at point c, but it is preferable that to causethe mesh type clutch to couple, the engine revolution number Ne isincreased to match the input/output shaft revolution number ratio Rch tothe speed changing ratio R2. This is disadvantageous since the number ofrevolution No of the output shaft 20 has been increased by the torquereduction correcting value corrected during the change-speed, if themesh type clutch is tried to be coupled at the time when the revolutionnumber of the input shaft 8 is in the direction of its decrease, torqueinterference occurs at the biting portions of the mesh type clutch,which makes the coupling difficult. This is because the way by which themesh type clutch is coupled in the direction in which the number ofrevolution of the input shaft 8 increases gives lesser torqueinterference.

Since after point c the relationship between Rch and R2 becomes Rch<R2,it is needed to increase the input/output shaft revolution number ratioRch. However, since just before the coupling (between point c and pointd), with the control of the engine torque Te a slight delay occurs inits response, it is preferable to adjust the input/output shaftrevolution number ratio Rch with the torque of the clutch 10. To thisend, during the period from point c to point d, the revolution numberratio FB target torque Tc_fb depending upon the deviation between theinput/output shaft revolution number ratio Rch and the speed changingratio R2 at the second speed is added, thereby to set the target torqueof the clutch 10 to Tc-ref=Tc-ff+Tc-fb.

As described above, by feeding back the input/output shaft revolutionnumber ratio during only a period in which the deviation between theinput/output shaft revolution number ratio Rch and the speed changingratio at the second speed is small, it is possible to restrain, to theminimum, the torque variation of the torque reduction correcting valueoccurring during the change-speed and it is possible to alleviate thesense of discomfort which the occupant receives. By such revolutionnumber ratio FB control of the clutch 10, the relationship of Rch R2occurs in the direction in which the input/output shaft revolutionnumber ratio Rch increases, and the mesh type clutch can be coupled atthe second speed.

When the mesh type clutch becomes the condition in which it can becoupled at the second speed, the control of the actuator 30 results inthe coupling of the mesh type clutch at the second speed. However, atthat time, it is preferable that by make smaller the deviation betweenthe torque reduction correcting value Tc_ref−Tc_ff+Tc_fb during thechange-speed and the torque of the output shaft 20 after thechange-speed (after the coupling at the second speed), the torque stepof the output shaft 20 at the end of the change-speed is reduced,thereby to suppress the occurrence of the shaft vibration.

Since the torque reduction correcting value during the change-speed isdetermined by the torque Tc of the clutch 10 and the torque of theoutput shaft 20 after the change-speed is determined by the torque Te ofthe engine 1 and the speed changing ratio R2 at the second speed,between point c and point d the throttle opening is controlled so thatit becomes ⊖=⊖_ref2, so as thereby to achieve the target torque Te_ref2of the engine 1. Since during the change-speed the clutch 10 is under aslippage condition, if the torque Te of the engine 1 is larger than apredetermined value, the torque reduction correcting value during thechange-speed is determined by the torque Tc of the clutch 10 and theinertia torque of the engine 1, whereby it is possible to perform thetorque matching control at the end of the change-speed independently ofthe torque reduction correcting control during the change-speed.

When at point d the actual change-speed is completed by the fact thatthe mesh type clutch is coupled to the second speed, the throttleopening ⊖ is returned gradually to the opening before the change-speedand at point e the speed changing control is finished.

As explained above, in accordance with this embodiment, in the speedchanging operation by finding the torque reduction correcting value ofthe output shaft 20 during the change-speed, controlling the revolutionnumber of the input shaft 8 on the basis of this torque reductioncorrecting value, and at the end of the change-speed adjusting thetorque of the input shaft 8, the torque variation of the transmissionoutput shaft 20 can be suppressed.

Next, a construction of the control device for a vehicle according tothe other embodiment of this invention will be explained using FIG. 8 toFIG. 11.

FIG. 8 is a block diagram for the control device according to thisembodiment. Since the overall system construction of the vehicle is thesame as one in the embodiment shown in FIG. 1, its explanation isabbreviated. Also, constructive parts in this embodiment equivalent tothe constructive parts in the embodiment in FIG. 1 will be explainedaffixing thereto the same reference numerals.

A control device 800 comprises the vehicle speed detecting means 101,the change-speed command generating means 102, the torque reductioncorrecting means 103, revolution number controlling means 801 and torqueadjusting means 802.

Since the control processes preformed in the vehicle speed detectingmeans 101 and the change-speed command generating 102 are similar tothose in the embodiment shown in FIG. 1, the explanation therefor isabbreviated.

Now, the control for the clutch 10 and the motor 27 at the time when thechange-speed is carried out from the first speed operation state to thesecond speed operation state will be explained using FIG. 9.

When the change-speed command Ss is output by the change-speed commandgenerating means 102, the mesh type clutch (hub 17) is made theuncoupled condition to release the coupling between the gear 18 and theoutput shaft 20, as shown in FIG. 9. At that time, the clutch 25 hasbecome coupled by the control of the actuator 29. At that time, thetorque of the motor 27 is transmitted along a motor torque transmittingpath passing the output shaft 26 of the motor 27, the clutch 25, thegear 24, the gear 7, the input shaft 8, the gear 5, the gear 9, theclutch 10 and the output shaft 20 in the order, whereby the revolutionnumber control and the torque adjustment for the input shaft 8 by themotor 27 becomes possible.

During the change-speed, the torque of the engine 1 is transmitted tothe output shaft 20 through the gears 5 and 9 by pressing the clutch 10under the control of the actuator 31. By this pressing pressure for theclutch 10 the torque of the engine 1 is transmitted to the axle 22 to beused as the driving torque of the vehicle, and the revolution number ofthe engine 1 is decreased because the load of the engine 1 becomeslarger as a result of the small speed changing ratio by the use of thegears 5 and 9, whereby the speed changing ratio between the output shaft20 and the input shaft 8 approaches the speed changing ratio of thesecond speed (the sense in which it becomes smaller) from the speedchanging ratio of the first speed.

At that time, the torque of the engine 1 is transmitted along atransmitting path passing the output shaft 3 of the engine 1, the clutch4, the input shaft 8, the gear 5, the gear 9, the clutch 10 and theoutput shaft 20 in the order. Then, when the speed changing ratiobetween the input shaft 8 and the output shaft 20 becomes the speedchanging ratio of the second speed the gear 11 and the output shaft 20are coupled by coupling the mesh type clutch to the gear 11. As soon asthe mesh type clutch is coupled to the second speed state, the actuator31 is controlled to release the pressing pressure of the clutch 10,whereby the change-speed is completed.

As mentioned above, although at the time of the change-speed the neutralstate occurs by releasing the first speed, since at that time the torqueof the engine 1 and the motor 27 is transmitted to the axle 22 throughthe output shaft 20 by the clutch 10 and the gear 5 and 9, it ispossible to correct any torque reducing portion occurring during thechange-speed.

Now, a control method at the time of the change-speed in the controldevice for a vehicle according to this embodiment will be explainedusing FIG. 10 and FIG. 11. Incidentally, since the control processes inthe torque reduction correcting means 103 are equivalent to thoseexplained using FIG. 5, the explanation therefor is abbreviated.

First, control processes in the revolution number controlling means 801and the torque adjusting means 802 will be explained using FIG. 10. FIG.10 is a flow chart for the control processes performed in the revolutionnumber controlling means 801 and the torque adjusting means 802.

Step 1001

In this step, it is determined whether the input/output shaft revolutionnumber ratio Rch found on the basis of the engine revolution number Ne(input shaft revolution number Nin) and the output shaft revolutionnumber No is within a predetermined range. If it is not within thepredetermined range, the process proceeds to Step 1002 in which thecontrol by the revolution number controlling means 801 is performed, andif it is within the predetermined range, the process proceeds to Step1005 in which the control process by the torque adjusting means 802 isperformed.

First, control processes in the revolution number controlling means 801which are performed in Step 1002 to Step 1004 will be explained.

Step 1002

The torque reduction correcting value Tc_ref found by Tc_ref=Tc_ff isread.

Step 1003

The target torque Tm_ref1 of the motor 27 which achieves the revolutionnumber Ne of the engine 1 effectuating a predetermined input/outputshaft revolution Rch is computed on the basis of the torque reductioncorrecting value Tc_ref read in Step 1002.

Step 1004

In this step, the target torque Tm_ref1 of the motor 27 found in Step1003 is output. The output target torque Tm_ref1 of the motor 27 is sentto the control device 35 through the LAN.

The control device 35 controls the motor 27 and the battery 28 toachieve the target torque Tm₁₃ ref1 of the motor 27.

As explained above, in the revolution number controlling means 801, itis possible to couple the mesh type clutch to the second speed bycontrolling the revolution number of the input shaft 8 during thechange-speed and it is also possible to improve speed changing abilityby suppressing the inertia torque occurring at the time of the secondspeed coupling.

Next, control processes in the torque adjusting means 802 preformed inStep 1005 to Step 1007 will be explained.

Step 1005

In this step, the torque reduction correcting value Tc_ref founded byTc_ref=Tc_ff+Tc_fb is read.

In this step, on the basis of the torque reduction correcting valueTc-ref read in Step 1005, the target torque Tm_ref2 of the motor 27which makes smaller the deviation between the output shaft torque afterthe change-speed and the torque reduction correcting value Tc_ref iscomputed.

Step 1007

In this step, the target torque Tm_ref2 of the motor 27 found in Step1006 is output. The output target torque Tm_ref2 of the motor 27 is sentto the control device 35 through the LAN.

The control device 35 controls the motor 27 and the battery 28 toachieve the target torque Tm_ref2 of the motor 27.

As explained above, in the torque adjusting means 802, by controllingthe torque of the input shaft 8 at the end of the change-speed, it ispossible to make smaller the deviation between the torque reductioncorrecting value during the change-speed and the torque of the outputshaft 20 after the change-speed, and it is also possible to improvespeed changing ability by reducing the torque step, thereby to suppressany shaft vibration occurring after the change-speed.

Next, the operation at the time of change-speed will be explained.

FIG. 11 is a time chart showing a control state at the time of thechange-speed. In FIG. 11, (A) indicates a change-speed command Ss, (B) ashift lever position Ii corresponding to a mesh type clutch position,(C) an input/output shaft revolution number ratio Rch, (D) the torque Tmof the motor 27, (E) the torque Tc of the clutch 10 and (F) the torqueTout of the output shaft 20. Also, the abscissa of this time chartindicates time.

As shown in (A), when the speed changing command Ss instructing thesecond speed is output at point a during traveling at the first speed,speed changing control is started, whereby as shown in (E) the torque Tcof the clutch 10 gradually increases.

As the torque Tc of the clutch 10 increases, as shown in (F) the torqueTout of the output shaft 20 gradually decreases and at point b the meshtype clutch which is being coupled at the first speed side becomesreleasable. That is, due to the torque transmitted with the gears 5 and9, the torque transmitted with the gear 7 and 18 decreases to a valuemaking the mesh type clutch releasable.

When the mesh type clutch becomes releasable by the control of theactuator 30 the mesh type clutch which has been coupled at the firstspeed side is released, whereby as shown in (B) the shift lever positionIi enters a neutral state (during the change-speed) and the actualchange-speed is started.

When the shift lever position Ii enters the neutral state, as shown in(E) the control of the clutch 10 for correcting the torque reductionpart occurring during the change-speed is started, and the actuator 31is controlled in accordance with the value of the target torqueTc_ref=Tc-ff of the clutch 10 output from the torque reductioncorrecting means 103, whereby as shown in (F) any torque reduction partof the output shaft 20 during the change-speed is corrected.

At that time, since the torque transmitted by the clutch 10 becomesequal to the torque of the output shaft 20, it is preferable that thetarget torque Tc_ref of the clutch 10 has a smooth property to reducethe sense of discomfort which an occupant would receive. Also, it isneeded to control, during the change-speed, the input/output shaftrevolution number ratio Rch rapidly and smoothly so that it becomes thespeed changing ratio R2 of the second speed.

Therefore, as shown in (D), the motor 27 and the battery 28 arecontrolled to obtain the target torque Te_ref I of the motor 27 outputby the revolution number controlling means 801, thereby to adjust theengine revolution number Ne, whereby the input/output revolution numberratio Rch is caused to be close to the speed changing ratio R2 of thesecond speed.

By such control of the clutch 10 and the motor 27, as shown in (C) theinput/output shaft revolution number ratio Rch becomes Rch=R2 at pointc, but it is preferable that to cause the mesh type clutch to couple,the engine revolution number Ne is changed toward its increase, therebyto match the input/output shaft revolution number ratio Rch to the speedchanging ratio R2. This is disadvantageous that since the number ofrevolution No of the output shaft 20 has been increased by the torquereduction correcting value corrected during the change-speed, if themesh type clutch is tried to be coupled at the time when the revolutionnumber of the input shaft 8 is in the direction of its decrease, torqueinterference occurs at the biting portions of mesh type clutch, whichmakes the coupling difficult. This is because the way by which the meshtype clutch is coupled in the direction in which the number ofrevolution of the input shaft 8 increases gives lesser torqueinterference.

Since after point c the relationship between Rch and R2 becomes Rch<R2,it is needed to increase the input/output shaft revolution number ratioRch. However, immediately before the coupling (during points c to d),both of the torque and the revolution number of the motor 27 must becontrolled. If as the motor 27 a motor that merely can carry out onlyone of the torque control and the revolution has been selected, it isneeded that the input/output shaft revolution number ratio Rch beadjusted by the torque of the clutch 10. To this end, during the periodfrom point c to point d, the revolution number ratio FB target torqueTC_fb depending upon the deviation between the input/output shaftrevolution number ratio Rch and the speed changing ratio R2 at thesecond speed is added, thereby to set the target torque of the clutch 10to Tc_ref=Tc_ff+Tc_fb.

As described above, by feeding back the input/output shaft revolutionnumber ratio during only a period in which the deviation between theinput/output shaft revolution number ratio Rch and the speed changingratio of the second speed is small, it is possible to restrain, to theminimum, the torque variation of the torque reduction correcting valueoccurring during the change-speed and it is possible to alleviate thesense of discomfort which the occupant receives. By such revolutionnumber ratio FB control of the clutch 10, the relationship of Rch R2occurs in the direction in which the input/output shaft revolutionnumber ratio Rch increases, and the mesh type clutch can be coupled atthe second speed.

When the mesh type clutch it can be coupled at the second speed, thecontrol of the actuator 30 results in the coupling of the mesh typeclutch at the second speed. However, at that time, it is preferable thatby make smaller the deviation between Tc_ref−Tc_ff+TC_fb correspondingto the torque reduction correcting value during the change-speed and thetorque of the output shaft 20 after the change-speed (after the couplingat the second speed), the torque step of the output shaft 20 at the endof the change-speed is reduced, thereby to suppress the occurrence ofthe shaft vibration.

Since the torque reduction correcting value during the change-speed isdetermined by the torque TC of the clutch 10 and the torque of theoutput shaft 20 after the change-speed is determined by the torque Te ofthe engine 1, and the torque Tm of the motor 27 and the speed changingratio R2 at the second speed, between point c and point d the motor 27and the battery 28 are is controlled so that the target torque Tm_ref2of the motor 27 is achieved. Since during the change-speed the clutch 10is under a slippage condition, if the sum of the torque Te of the engine1 the torque Tm of the motor 27 is larger than a predetermined value,the torque reduction correcting value during the change-speed isdetermined by the torque Tc of the clutch 10 and the inertia torque ofthe engine 1 and the motor 27, whereby it is possible to perform thetorque matching control at the end of the change-speed independently ofthe torque reduction correcting control during the change-speed.

At point d the actual change-speed is completed by the fact that themesh type clutch is coupled to the second speed. After the completion ofthe change-speed, the torque Tm of the motor 27 is returned to zerogradually, and at point e the speed changing control finishes.

As explained above, in accordance with this embodiment, in the speedchanging operation, by finding the torque reduction correcting value ofthe output shaft 20 during the change-speed, controlling the revolutionnumber of the input shaft 8 on the basis of this torque reductioncorrecting value, and at the end of the change-speed adjusting thetorque of the input shaft 8, the torque variation of the transmissionoutput shaft 20 can be suppressed, thereby to improve the speed changingability.

Incidentally, this invention is not intended to be limited to the systemconstruction in the above-mentioned embodiments. This invention isapplicable to a control device for a vehicle in which the motor 27 isnot used. Also, it is possible to use as the clutch 4 and the clutch 10all types of friction clutches including a dry type single plate clutch,a wet type multiple plate clutch, an electromagnetic clutch, etc.Further, it is possible to use as the clutch 25 all types of clutchesincluding a dry type single plate clutch, a wet type multiple plateclutch, an electromagnetic clutch, a mesh type clutch, etc.

Since this invention is constructed so that any torque variation of theoutput shaft occurring by the revolution number control carried outduring the change-speed and the torque of the input shaft at the end ofthe change-speed is adjusted, it is possible to reduce any torque stepof output shaft and suppress any shaft vibration, thereby to improvespeed changing ability for a vehicle.

The foregoing disclosure has been set forth merely to illustrate theinvention and is not intended to be limiting. Since modifications of thedisclosed embodiments incorporating the spirit and substance of theinvention may occur to persons skilled in the art, the invention shouldbe construed to include everything within the scope of the appendedclaims and equivalents thereof.

1. A method for controlling a transmission, which comprises a first gearpair for transmitting a torque from an input shaft to an output shaft, afirst dog clutch which meshes with said first gear pair, a second gearpair for transmitting the torque from said input shaft to said outputshaft, a second dog clutch which meshes with said second gear pair, athird gear pair for transmitting the torque from said input shat to saidoutput shaft, and a friction clutch for transmitting the torque to saidthird gear pair under an application of pressing force, said methodcomprising: engaging said friction clutch with said third gear pair;disengaging said first gear pair and said first dog clutch; controllinga rotational speed of said input shaft; engaging said second gear pairwith said second dog clutch; and disengaging said friction clutch fromsaid third gear pair.
 2. The method according to claim 1, wherein saidcontrolling step comprises controlling a rotational speed of said inputshaft such that a ratio between rotational speeds of said input shaftand said output shaft conform to a change-speed ratio of said secondgear pair.
 3. The method according to claim 1, further comprisingcontrolling the torque of said input shaft before and after engagementof said second gear pair with said second dog clutch.
 4. The methodaccording to claim 1, wherein said step of controlling a rotationalspeed of said input shaft comprises controlling an electronicallycontrolled throttle valve of an engine which is coupled to saidtransmission.
 5. The method according to claim 1, wherein said step ofcontrolling a rotational speed of said input shaft comprises controllingignition timing of an engine which is coupled to said transmission. 6.The method according to claim 1, wherein: at least after disengagementof said first gear pair and said first dog clutch, and before engagementof said second gear pair with said second dog clutch, said frictionclutch is engaged to said third gear pair; and the torque of said inputshaft is controlled.
 7. The method according to claim 6, wherein afterthe disengagement of said first gear pair and said first dog clutch, andbefore said second gear pair engages with said second dog clutch: saidfriction clutch is engaged to said third gear pair; and a rotationalspeed of said input shaft is controlled such that a ratio betweenrotational speeds of said input shaft and said output shaft conform tochange-speed ratio of said second gear pair.
 8. The method according toclaim 6, wherein before and after engagement of said second gear pairwith said second dog clutch, the torque of said input shaft iscontrolled.
 9. The method according to claim 6, wherein torque of saidinput shaft is controlled by an electronically controlled throttle valveof an engine which is coupled to said transmission.
 10. The methodaccording to claim 6, wherein torque of said input shaft is controlledby ignition timing control of an engine which is coupled to saidtransmission.
 11. The method according to claim 1, wherein: when saidsecond gear pair and said second dog clutch are disengaged, the torqueof said input shaft is controlled.
 12. The method according to claim 11,wherein: after disengagement of said first gear pair and said first dogclutch and before engagement of said second pair with said second dogclutch, said friction clutch is pressed to said third gear pair; and arotational speed of said input shaft of the transmission is controlledsuch that a ratio between rotational speeds of said input shaft and saidoutput shaft conform to a change-speed ratio of said second gear pair.13. The method according to claim 11, wherein before and afterengagement of said second gear pair with said second dog clutch, thetorque of said input shaft is controlled.
 14. The method according toclaim 11, wherein the torque of said input shaft is controlled bycontrolling an electronically controlled throttle valve of an enginewhich is coupled to said transmission.
 15. The method according to claim14, wherein the torque of said input shaft is controlled by controllingan electronically controlled throttle valve of an engine which iscoupled to said transmission.
 16. The method according to claim 11,wherein the torque of said input shaft is controlled by controlling anignition period control of an engine which is coupled to saidtransmission.
 17. Controlling apparatus for a transmission whichcontrolling apparatus controls a first dog clutch for meshing with afirst gear pair which transmits torque from an input shaft to an outputshaft, a second dog clutch for meshing with a second gear pair whichtransmits torque from said input shaft to said output shaft, and afriction clutch for transmitting the torque to a third gear pair whichtransmits torque from said input shaft to said output shaft under anapplication of a pressing force; wherein said controlling apparatuscontrols said transmission according to the following sequence: saidfriction clutch engages with said third gear pair; said first dog clutchdisengages from said first gear pair; rotational speed of said inputshaft is controlled; said second dog clutch engages with said secondgear pair; and said friction clutch disengages from said third gearpair.
 18. The apparatus according to claim 17, wherein: at least afterdisengagement of said first gear pair and said first dog clutch, andbefore engagement of said second gear pair with said second dog clutch,said friction clutch is engaged to said third gear pair; and the torqueof said input shaft is controlled.
 19. The apparatus according to claim17, wherein after the disengagement of said first gear pair and saidfirst dog clutch, and before said second gear pair engages with saidsecond dog clutch: said friction clutch is engaged to said third gearpair; and a rotational speed of said input shaft is controlled such thata ratio between rotational speeds of said input shaft and said outputshaft conform to change-speed ratio of said second gear pair.
 20. Theapparatus according to claim 17, wherein before and after engagement ofsaid second gear pair with said second dog clutch, the torque of saidinput shaft is controlled.
 21. The apparatus according to claim 17,wherein torque of said input shaft is controlled by an electronicallycontrolled throttle valve of an engine which is coupled to saidtransmission.
 22. The apparatus according to claim 17, wherein torque ofsaid input shaft is controlled by ignition timing control of an enginewhich is coupled to said transmission.
 23. The apparatus according toclaim 17, wherein: when said second gear pair and said second dog clutchare disengaged, the torque of said input shaft is controlled.
 24. Theapparatus according to claim 17, wherein: after disengagement of saidfirst gear pair and said first dog clutch and before engagement of saidsecond pair with said second dog clutch, said friction clutch is pressedto said third gear pair; and a rotational speed of said input shaft ofthe transmission is controlled such that a ratio between rotationalspeeds of said input shaft and said output shaft conform to achange-speed ratio of said second gear pair.
 25. The apparatus accordingto claim 17, wherein before and after engagement of said second gearpair with said second dog clutch, the torque of said input shaft iscontrolled.
 26. The apparatus according to claim 17, wherein the torqueof said input shaft is controlled by controlling an ignition periodcontrol of an engine which is coupled to said transmission.